This invention relates to an earth working tool assembly and in particular to a method and means for reinforcing the shank of an earth working tool to increase the resistance of the tool shank to side loadings on the tool point attached to the tool shank.
Many earth working tools as used in agricultural equipment include a shank which is provided at its lower end with a replaceable or detachable point for penetration of the earth being worked by the tool. So as to reduce disturbance of the earth, the tool shank is usually made relatively narrow in width at least adjacent to its lower end. As a result side loadings applied through engagement of the tool point with the earth and meeting obstructions during ploughing or other earth working can cause bending of and thus damage to the tool shank. In some cases, the tip of the tool shank can be broken off.
A further consequence is that the tool point can become detached from the tool shank. This may arise because the tool points usually include a rearwardly directed socket for engagement with the tool shank tip which is partially split on its underside and excessive ride loading on the tool point can cause the socket to expand and the point to become loose.
Whilst the above disadvantages can be overcome by increasing the width of the tool shank, this has an adverse effect on ploughing or other earth working operations. Similar disadvantages occur if the tool shank is reinforced on one or both sides.
The present invention aims to overcome or alleviate one or more of the above disadvantages by providing a method of, and means for, reinforcing a tool shank of an earth working tool which will function to improve the capabilities of the earth working tool. The present invention in a further aspect aims to provide an improved arrangement for retaining an earth working tool point to a tool shank. Other objects and advantages of the invention will become apparent from the following description.
The present invention thus provides in a first aspect an earth working tool assembly comprising:
a tool shank having a front end;
an earth working point having a rear end detachably engaged with said front end of tool shank; and
load transferring means extending from the rear end of said point and engaging said tool stank at a position rearwardly of said front end thereof to transfer at least a proportion of the side loadings on the tool point to the shank at said position rearwardly of said front end.
The tool shank and point have lower or under sides and preferably, the load transferring means is engaged with the lower or under sides of the shank and point so as not to substantially increase the width of the tool shank. Typically, the shank has a lower foot portion for engagement with the tool point, the foot portion extending forwardly of the main leg of the shank and the tool point has a socket for complementary receipt of the foot portion of the shank. Alternatively, the shank may have at its lower end a socket for receipt of the tool point, the point for this purpose having a rear part for complementary engagement in the socket of the tool shank.
The load transferring means may be formed integrally with the tool point however preferably, the load transferring means comprises a separate bridging member which connects both with the tool point and shank. Preferably, the bridging member is slidably engaged with the shank. Complementary male/female engagement means are preferably provided between the bridging member and point and shank. The complementary male/female engagement means between the tool point and bridging member may comprise a longitudinally extending rib on the underside of the point and a channel in the bridging member for complementary receipt of the rib. Keying means may be provided for keying the point to the bridging member. The keying means suitably comprises opposite recesses in the rib of the tool point and the channel of the bridging member, the recesses being aligned with a key extending into both recesses, the key preventing longitudinal movement between the rib and channel.
The complementary male/female engagement means between the tool shank and bridging member may comprise a channel on the lower side of the shank and a complementary tongue on the bridging member slidably receivable in the shank channel. Connecting means may be provided for positively securing the bridging member to the tool shank. The connecting means suitably comprise a nut and bolt connection between the tongue of the bridging member and the channel of the tool shank. The nut and bolt connection may comprise a nut captured against rotational movement in the tongue of the bridging member, and a bolt supported to the shank and extending into the channel for engagement with the nut. Preferably, the channel includes an end wall through which the bolt passes for engagement with the nut whereby tightening of the bolt draws the tongue along the channel.
Preferably, the bridging member has a region of increased sectional modulus between the tongue and channel of the bridging member for providing effective support to the shank.
In a further aspect, the present invention provides a method of reinforcing the shank of an earth working tool of the type having a point detachably engaged therewith, said shank having a front end, and said point having a rear end engaged with said front end of said shank, said method including the steps of:
providing load transferring means, said load transferring means extending from the rear end of said point; and
connecting said load transferring means to said shank at a position rearwardly from said front end of said shank whereby a proportion of side loadings on said point is transferred to said shank rearwardly of said front end thereof.
In yet a further aspect, the present invention provides a tool point adapted for engagement with a tool shank, said point having a rear end engageable with a front end of said tool shank and a lower side; said point having:
means on said lower side thereof adapted to engage a load transferring member connectable to said tool shank for transferring at least portion of the side loadings on said tool point to said shank at a position rearwardly of said front end.
Suitably the means on the lower side of the point comprises longitudinally extending rib means for engagement by the load transferring members. Preferably, the shank has means on the underside thereof for engagement by a loading transferring member. The means on the underside of the shank may comprise a channel for receipt of the load-transferring member.
Alternatively, the means on the lower side of the point may comprise a channel for receipt of the load transferring member and the means on the lower or underside of the shank may comprise rib means for engaging the load-transferring member.
Preferably the rib on the point and channel on underside of the shank are cast in steel integrally with the point and shank respectively however they may be separately attached such as by welding. The bridging member is also suitably comprise a metal casting however it may be fabricated from steel or other metal.